The number of American Indians (AIs) diagnosed with AIDS has risen more rapidly than among any other ethnic group, increasing almost 8-fold in the 1990s. In addition, with more than 20 percent of AIDS cases diagnosed among persons in their 20s, many individuals contract HIV as teenagers and young adults. Overall, though, the success rates to date of preventive interventions with adolescents have not been consistent, persistent, or encouraging. What is currently missing is theoretically driven, developmentally focused prevention-oriented research that seeks to understand how youth maintain protective HIV knowledge, attitudes and behaviors (KABs) and avoid KABs that put them at risk; preventive interventions can then help both to enhance these competencies and to eliminate risks. I propose to generate and test a developmental theory for the prevention of high-risk HIV knowledge, attitudes, and behaviors among adolescents and young adults. Using 2 Al data sets-a cross-sectional community-based stratified random sample (N=514) and a high-school-based longitudinal data set covering 6 years from adolescence to young adulthood (N=372) will use psychiatric epidemiology and developmental psychopathology frameworks to guide analyses and Social Cognitive Theory and Stress-Vulnerability Theory to select constructs to be utilized in these frameworks. This project will help to advance theory testing around processes leading to HIV risk/protection. This underlying developmental theory of prevention will be used to guide the selection, design, and adaptation of community-based, culturally appropriate HIV preventive interventions for this age group. This K02 application unites 4 strands of my professional interest: 1) adolescent development; 2) challenging settings (e.g., ethnic minority communities); 3) preventive interventions; and 4) quantitative methods. With this application, I have 4 career objectives: 1) to learn more about behavioral research about HIV/AIDS, 2) to immerse myself in epidemiology/developmental psychopathology frameworks, 3) to enhance my statistical training, and 4) to advance my expertise in preventive interventions. The Psychiatry Department at UCHSC is internationally renowned for its research in human and primate development; it also boasts the country's largest and most productive research program in American Indian/Alaska Native mental health, of which I am a part.